retreiving address from mail

Does anyone know how tostore the address from teh drop down when you go to send an email in mail. For some reason I dont have these addresses in my address book, but i have hundress of address that show up if i go to send an email. When I go new, and I go to enter the email address of the person I am sending to, it shows me a list of the addresses I have that start witht aht letter.

Also... if you mouse over any address anywhere in Mail (10.4), it will make it into a 'blob' that you can drag, drop, etc... *and* you'll see a little triangle on the right side. Click it, and a contextual menu pops down that includes "Add to Address Book". (Right- or ctrl-clicking on the address will do the same thing, of course.)

The Prev Rcpts window is good for batch adding, but this is more useful for one-offs as they come in.